Motion feedback in conventional lighting control systems is implemented using additional sensors such as PIR (passive infrared) to implement automatically-activated lighting systems. The infrared detectors can detect infrared radiation emitted by an object/moving object. This is a costly approach, especially considering installation cost.
Other motion sensors based on sonic or ultrasonic/acoustical detectors, break-beam (active) devices, video systems and the like, which are used in motion/intrusion detection, can be also used to control lighting. The challenges which still remain are device and installation cost for all approaches, false alarms (e.g., for acoustic detectors), susceptibility to environmental changes (e.g., for acoustical detectors and PIR devices), difficulty of identifying motion, directionality and distance information (e.g., for acoustical, PIR and break-beam devices), unrealistic memory requirements (for video system), etc.